Brake pedal goes to the floor after replacing front brake pads, calipers and rotors

Hello and thank you for stopping in to share your troubles. Lets see what I can do to help you.
First please watch this link on how to bleed brakes by yourself.

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

If you have followed these procedures and they are fully bled and the pedal still goes to the floor then it sounds like your master cylinder plunger seals may have blown in which case you will need to replace the master cylinder. If this turns out to be the case, here is a link that shows you how to replace and bleed the new cylinder and then bleed the whole system.

If you have any questions please feel free to come back to this post and ask. And make sure you let us know how it went if this resolves your issues.

Have a great day! Rich